diff --git a/public/sw.js b/public/sw.js
index d0c4438..b6f5b07 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -118,6 +118,12 @@ self.addEventListener('message', (event) => {
 
 // 🚀 FETCH: Offline-First Strategy
 self.addEventListener('fetch', (event) => {
+    // 🛡️ SECURITY/STABILITY: Only process http/https schemes.
+    // Prevents "Failed to execute 'put' on 'Cache': Request scheme 'chrome-extension' is unsupported"
+    if (!event.request.url.startsWith('http')) {
+        return;
+    }
+
     const url = new URL(event.request.url);
 
     // CRITICAL: Bypass Auth/API/Supabase early and COMPLETELY.